Telephone-exchange system



w P ALBERT TELEPHONE EXCHANGE SYSTEM b Filed April 13, 1921 5 sheetsshea 2 a Mmh 1o. 1925'.

1,528,746 W. P. ALBERT TELEPHONE EXCHANGE SYSTEM 5 SheetsSheet 3 Filed 'Apil 13, 192;`

` March l0. 1925. K

w. P. ALBERT TELEPHONE EXCHANGE SYSTEM w. P. .M BER'i TELEPHONE EXCHANGE SYSTEM March 1o. 1925.

S sheets-sheet s Filed April 13, 1921 Patented Mar. 10, 1925.

UNI T E D lS TA TELS WALTER r. Ari-BERT, or" rrAsT- oRANGnNEW- JERSEY, As'srelvon To WnsT-ERNELECJ Tmc COMPANY, `Inco-rfi'ronurafa-n, er NEW YORK, N. Y., A conroniATIon or NEW YORK.

TnLsr-HoNEmXoHANGE SYSTEM.

Y fApplcatinled April 13, 1921. VSerial No. 460,888.

To all fic/mm thirty concern.' n

Be it known that I, VALTER P. ALBERT, a citizen of V the United States, residing at East Grange, in the county of Essex, State ot New Jersey, have invented certain new and useful In'iprovements in Telephone-EX- change Systems, of which the following isa t-ull, clear, concise, and exact description.

vThis invention relates to improvem-ents in automatic telephone exchange lsystems and more particularly to improvements in telephone exchange systems of large capacity.

More specifically the invention is jan improvement Ion systems of` the type lshown in a patent to A. E. Lundell and J. J. Wynne, No. 1,501,676, in which a translator' switch with its attendant advantages inthe way of commoncross connections through `a common limpulse generating device, is utilized.

Itis the objectofthis invention to provide system in which a translator switch is employed which 4may be positioned under the control ot a calling subscriber, and in which registrations are transferred "from such Atranslator switch to secondary registering devices where they are usedto control a sending device.

-A feature ot' the linvention is `the method employed `for transferring -the registration trom the translator switch to the secondary registers f f Other features reside in novel controlling circuits.

lt is thought that the invention will best be understood from-the yfollowing detailed description, reference being had'to'the accompa-nylugdrawings.l n

Refer-ring to the drawings, Figures 1, 2 and 3 when taken in order fromV lett y to right,-with Fig. 4 beneath Fig. 2, and Fig. 5 atthe right of Fig. 4, illustratea .portion of the circuits and apparatus of'a telephone oiice in which' the present invention is contained.

In Fig. 1 isshown `a calling subscribers line terminating in an individual line switch adapted to extend theline to an idle trunk circuit.

Fig. 2 illustrates atrunk circuit accessible to the individual line switch and which terminates in a irstor district selectorswitch. This ligure also shows a step-by-step sender selector switch -tor associating the circuits ot thedistrict switch with one of a plurality ot register sender mechanisms,

Fig. 8 shows a second or otlice selector switch accessible to the district switch and which' serves to extend the calling line over trunks to other switches either in the same or in distant otices.

Fig. y4 illustrates a sender and controlling mechanism arranged to receive series of impulses transmittedover a calling subscribers line. torecord the oilice and numerical desi gnation ot a called subscribers line and to control the automatic switches for the purpose of extending a connection in accordance with the registered designation. This tiguse also illustrates aAV class switch., the function ot which is to govern the sending mechanism in accordance with the class ot the call recorded.

Fig'. 5 shows diagrammatically a two movement step-by-stepswitch arranged to be positioned directly by impulses trom the calling subscribe-rs line to determinel the routing of the connection to the proper oiiice. This figure also shows an impulse generating device common to all the senders Aof the eX- change, and a set of register relays tor controlling the counting .relays ot Fig. 4. A plurality ot' step-by-step registers are also indicated., their function being to record the numerical designation of the desired line in the called otlice.

The individual line switch of Fig. 1, the sender selector of 9., the progression switch ot Fig. 4, and the step-by-step registers-of Fig. 5 are preferably of a. mechanical construction, similar to that shown yand de- .f

scribed in a patent to O. F. 4Forsberg and De Vignier No. 1,472,465.

The district and ofiice switches are of the well-known power driven panel type, a complete description beinogiven in the patent to Craft and Reynolds, 1,123,696, issued January 5, 1915.

The sequence*switchesQlO, 310, 410 and 440 are the same instructnre and principle as' the one illustrated'in detail in the patent to Reynolds and Baldwin, 1,127,808, issued February' 9, 1915. The sequence switches 210 and 310 control respectively the contacts shown in Figs. 2 and 3. In Fig. 4, however, the sender sequence switch 44() governs all contacts shown in the space above and to the right ot the broken line, while the class sequence switch 410 controls the re'- maining contacts.

In the lower part of Fig. 4 a progression switch is provided having tive brushes 411, 412, 413, 414 and 415, each cooperating with a circular row of terminals. This switch performs the necessary change over :tunetions for associating the impulse circuit in succession with the translator switch and with the registers shown in Fig. 5.

The translator switch of Fig. 5 comprises an ordinary step-by-step switch having a primary vertical movement and a secondary rotary movement, and is arranged to operate a brush set comprising five brushes mounted on the same shaft.

The first two series ot' impulses cause the setting et thel translator switch, identitying the particular ofiice to which the connection is to be extended. According to the manner in which connections arc handled in the called oiiice, as tor example, in a full mechanical or semi-mechanical manner, the class sequence switch 410 takes up a setting to govern the operation of the sender in controlling` the extension of the particular connection involved. Some ot the outlying offices served through the ofiice shown in the drawing will be provided with switches for handling incoming calls on a full mechanical basis. Calls to these ofiices constitute one class. Again other oiiices will be equipped with call indicators at an operators position for completing the con nections manually. These oiiices will constitute another class. Similarly there may be several other classes of calls that will have to be taken care of. F or this purpose the class sequence switch 410 is provided and is variably set, as will hereinafter be explained in detail, in accordance with the terminal on which the brush 511 is positioned, under the control of the impulse generating device.

The first two series of impulses sent by the subscriber to position the translator switch determine the district brush, district group, otiice brush and oiiice group selections to select a trunk, such as trunk 328, 329 leading to the cflice containing the called line. ln other words, the firs-t two letters or numerals identifying the called -ofiice determine the vertical and rotary movements ot the translator switch for the purpose ot selecting this ofiice.

Following the transmission of the tirst two series of impulses for setting the translator switch, a subscriber sends four series ot impulses to identify the digits of the called line party by causing the variable setting ot the numerical registers. The banks ot each ot' these registers may be wired in any convenient manner to the counting relays in order to control incoming and filial switches or call indicators either in the local oiiice or in a distant otiice selected by the district and office switches illustrated in Figs. 2 and inasmuch as the present invention relates more particularly to the translator switch and the register relays of Fig. 5 and the manner ot controlling the same, it has not been considered necessary to illustrate and describe Athe controlling` mechanism in further detail nor to show the different types of apparatus that may be installed in distant called oitices.

A detailed description of the operation of the system will now be given. F or this purpose it will be assumed that the sub.- scriber of line desires to converse with a subscriber whose line terminates in an ofiice identified by the code No. 37'. ln practice it is probably more convenient to identify the ofiices by letter codes which may be taken as abbreviations of the names of the offices. For example, the called ofce may be known by the code A B and the manipulation of the subscribers dial 101 to transmit the letters A B would in efect cause the transmission of the digits 3 and 7.

To initiate a call the subscriber removes his receiver from the switchhook whereby a circuit is established from battery through the right-hand winding of line relay 103. back contact and inner lower armature ot relay 104, over the loop ot the calling substation 100, to ground at the upper armature and back contact of relay 104. Relay 103 becomes energized and completes a circuit from battery through the winding of stepping magnet 105, armature and contact of said magnet, lowermost armature and contact of relay 104, right-hand armature and front contact of relay 103 to ground through the brush 111 and terminal 114. Magnet 105 energizes, interrupts its own circuit, deenergizes, and steps the brushes 106, 10", 10S, 109, 110 and 111 forward one step. Brush 109 thereupon engages the segment 113 and battery potential is supplied to the test terminal 102 of the calling line 100 in the multiple banks ot all final selector switches having access to this line. In this manner the calling .line is rendered busy. The above traced circuit is again completed tor magnet 105 by way of brush 11 and terminal 119, and the switch continues to the next set of terminals which represent the first ot' a plurality ot trunk circuits leading to district selector switches. So long as the individual switch encounters the terminals of busy trunks. brush 111 finds a ground potential on the test terminals 120 of such trunks and the switch continues to rotate. 'Vhen the first idle trunk 115, 116 is reached no ground potential is present on terminal 120 and. consequently, the stepping magnet 103 ceases to advance the switch.

Since the trunk 115, 116 is idle, the sequence switch 210 of the district switch associated with such trunk is standing in position 1. A circuit isvthen iclosed from hatterythrough contact of sequence :switch spring, 203,1bacl; cont-act and left-hand armature ot' relay 206, conductor 118, terminal 120, brush 111, Contact, lettshandA armature and left-hand winding of relay 103, through both `windings oit/"relayl 104i-, in series, to ground. IRelayl 104 becomes energized in this circuit and locks up in a circuit as follows: battery, through the fore=break contact of relay 205, lower contact of sequence switch spring 245, con` ductor 117, terminal 121, brush 110, middle lower armature and Contact ofrelay 101, upperwinding of said relay to ground. Re-

lay 101,:therefore, remains energized, while g relay 206 also lattracts its armatures. Relay 200, at its left-hand armature 4'and baci; contact, opens the 4circuitthroughuthe letthand winding of rrelay 103, whichwcaused the original energization of relay 104. .Re-

lay 103, consequently, becomes deenergized.

Relay 206, on attracting its amatures, completes a circuit lfrom battery vthrough the right-hand winding votrelay212, klower left-hand contact of sequence switch spring4 211i, contacts of sequence switch spring 208, to ground at the ycontact and'y right-:hand armature of relay 206. 'Relay v212 becomes energized and closes a circuit'from grounded battery through thevwinding o1A sequence switch magnet 210V, deft-hand contact .of sequence switch spring 215, front contact and right-hand armature of relay 212, lower contact of sequence switch spring 213 to ground. Sequence switch v 210 advances `from position 1 to positionk 2. A circuitr is now closed from ground lover the upper from battery through the lefthand winding f.

and contact and lefty-hand armature of relay 212, upper left-hand contact ofsequen'ce switchspring 251, lower contact of sequence switch spring 220, conductor 252, brush 241, thence over the multiple of 'the test'V terminaly individual to lthe busy sender,;=to t-he brush 241 of the sender selector that is rendering said sender busy, tonground atthe inner left-hand`armaturei of theoperated relay corresponding to therelay,V 207, shown in the figure. energized in position 2 of sequencer switch 210, and, in so doing, provides a circuit for the stepping magnetV 211 for advancing the ylirushes `239, 240, 24.1, 242, 243,' and switch*` spring 209.

yrelay-400 of said sender.

RelayL 212 remains 24e-of the sender selector .switch shown, to searchfiorzthe terminals :of an idlev sender. The circuit for magnet 21,1m-ay be-tollowed fromagrounded battery through the Contact,

armature and winding ofsaid magnet,`con djuctory253; leftfhand Contact of sequence switch spring I218, front contact and-right- -liand armature; of relay 212,'-lower contact `oli-,sequence 4switchspring 213 'to ground. .At the same timeA av circuit is maintained winding of 'relay 206, left-hand make-bc-` from rbattery-through the. contact, armaturelandfwinding of magnet 211, through thewwinding of relay,1207,. to ground at :the3lower left-hand contact of sequence Due, however, to they own 'circuit and advances Athevbrushes 'otrthe sender selec-tor inl a step-bystep movement to search for an idley register sender.

When the'rstfidle sender isfreached, relay .,212 becomes'.deenergized since noA ground potential l1s oundon the-'multiple terminal;

engaged by'thevtest brush 211.V Relay-212 `opens the direct circuit to groundiorfthe magnet l211. Magnet 211 is nowincluded inseries withl relay 207, and this relay attracts. its armatures. TheV magnet 211idoes' not continue to operate in view of ,the high resistanceaot' relay 207. g Relayj207, at its inner lett-hand' armature, yappl-ies a ground potential tothe test terminal to render the vselected sender busy to othersender `selec-1v tor switches. Relay 212, onretracting-its armatures, completes a circuit as follows for driving the sequence switch 210 outl ot position 2 and into position 3: battery, throughthe,winding of the power magnet of said sequence switch, right-hand -contact ofv sequence switch lspring 215, bach contact .and rightfhand armature of relay 212, lower Contact of sequence switchspring 213 tol ground. Relay 207 also closes a. circuit from ground Vover its inner left-hand armature, brush 241, contacts ofvspring i051 Aof the class Asequence switch L110', winding of relay 402 tol battery and ground. Relay 402 -lockslup over its inner armature and at its outer armature closes a circuit by way off the upper leftfhand contact 'offsequence switch spring 108 tor driving sequenceswitch410 into position 8,

An idle sender having been selected, and with sequence switch 210-in position 3,1m impulse circuit is established from the calling subscribers line through to the impulse This circuit may be tracedtrom battery through the winding of impulse-relay 400,"brush 240, outer lefthand armature and contact 'of 1elayf207, lower contact of sequence switch-spring 201, conductor 116,'tern'1inal 122, brush 108, frontcontact and inner lower armature of relay 104, through the loop of substation 100, upper armature and front contact of relay 104, brush 106, terminal 123, conductor 115, left-hand contact of sequence switch spring 200, brush 239, right-hand winding of coil 401, to ground. Relay 400 becomes energized and completes a circuit over its armature and front contact for the slow to release relay 404. Relay 404 closes a circuit from ground through its outer left-hand armature and contact, conductor 425, vertical olf normal contact 531, winding of relay 500 to battery and ground. Contact 531 is controlled by the shaft of the translator switch and is closed during the time said shaft is in its normal position. Relay 404 also completes a circuit from ground through the right-hand vinding of the tone coil 475, left-hand winding of coil 401,` inner left-hand armature and contact of relay 404, conductor 409, terminal 434, brush 414 of the control switch, to ground. Current flowing in this circuit induces a current Iin the right-hand winding of the coil 401, which is transmitted over the impulse circuit above traced, to produce a characteristic sound in the calling subscribers receiver. This sound indicates that a sender has been associated with the calling line and that the subscriber may proceed to transmit impulses.

The subscriber thereupon operates the sending dial 101 to transmit the first digit 3 of the code identifyingthe ofce in which the called line appears. The first interruption of the impulse circuit .causes the deenergization of relay 400, which completes a circuit from ground through its armature and baclr contact, righthand armature and front contact of relay 404, winding of the slow to release relay 405, brush 412, terminal 417, conductor 424, inner right-hand armature and front Contact of relay 500, conductor 529, winding of the vertical stepping magnet 504 to battery and ground. The retraction of the armature of relay 400 also completes a circuit from battery through the winding of rela-y 406, brush 413, terminal 4353, conductor 422, contact and outer left-hand armature of relay 500, conductor 560, contact and armature of magnet 504, conductor 529, front contact and right-hand armature of relay 500, conductor 424, terminal 417, brush 412, winding of relay 405, front contact and right-hand armature of relay 404 to ground at the back contact and armature of relay 400. Relay 406 becomes energized and completes a circuit from ground through its outer armature and contact, winding of relay 405, brush 412, terminal 417, conductor 424, and thence, as above traced, through the winding of magnet 504 to battery and ground. Relay 40G, is, therefore, energized in a circuit which depends upon the armature and contact of the vertical stepping magnet 504, and as long as it remains energized a circuit for said magnet is maintained independently of the armature and back Contact of relay 400. Should the opening period of the line circuit be abnormally short due to an imperfect dial, or for any other reason, the consequent attraction of the armature of relay 400 does not cause the premature opening of the circuit of the stepping magnet 504. The magnet 504 remains energized, depending upon the relay 406, until ithas had time to advance the brushes of' the switch a full step to position them opposite the first levels of terminals. l-Vhen the full step has been completed the armature and Contact of relay 504 are opened and the circuit of relay 406 is interrupted. Relay 400 thereupon releases its armatures and opens the circuit of the magnet 504, which in turn becomes deenergized. Relay 400, furthermore, maintains a circuit at its inner armature and contact for the slow to release relay 404. Relay 404 is designed to remain operated during the normal periods in which its circuit is opened by the armature of relay 400. If, however, relay 400 remains deenergized for an exceedingly long period, relay 404 cannot become deenergized due to the fact that relay 406 provides a substitute holding circuit therefor.

As the translator switch takes its first step, the contact 531 is opened to interrupt the original energizing circuit of relay 500. Relay 500, however, remains energized in a. circuit as follows: from grounded battery, through the winding and front Contact and inner left-hand armature of relay 500, conductor 423, contact and armature of the slow to release relay 405, to ground. Relay 405, being of the slow-to-release character, does not retract its armature during the brief interrupt-ions of its circuit at the armature and back contact of the stepping relay 400. On each of the following interruptions of the line circuit in the transmission of the iirst digit, the brushes 511, 514, and 515 of the translator switch are advanced one step until they are finally positioned opposite the third level of terminals in their respective banks. Following the third impulse, the stepping relay 400 remains energized for a comparatively long period, during which interval the slow-to-release relay 405 is permitted to release its armature. Relay 405 opens the holding circuit of relay 500, which becomes deenergized.

The calling subscriber next operates the sending dial 101 to transmit a series of seven impulses representing the second digit of the oliice code. On the first opening of the impulse circuit, relay 400 becomes deenergized and vcompletes a circuit from ground through its armature and back contact, right-hand armature and front conf) fi Cil tery, throughv ther winding-fot-said relay,

bruslr413;terminal-433,5conductor lett hand normal Contact ot relay `300,1conductor- 562, contact and armatureot" stepping ;1nagnet 503, comlnt'torl 561', andfthence toground, asrabove traced, at the baclrcontactf and armature lot relay 400. f Relay' 406,l 1n a manner simil-ar to* that previously described,

closes a circuit for thelrotary stepping magnet 503 fto insure that said'i magnet taires-a liu/ll step betere its circult is opened.` For each ot the-seven `impulses-ot ithersecond digit 'the brushes of the translator sxvitcli are `advanced one step over the third leve-ls of terminals and' arerfinallv brought to're'stin` engagement with the seventlrset `oi terminals 1n such level. The slow-torelease-relay 405, which also becomes energized during.

the transmission Lof the second series offim` pulses,rcompletes a circuit ron'r ground through itsarmat'ureand Contact, conductor 423, inner left-:handV7 armature and Aback Icon- I tact ot relay 500, conductor427, wlndrngfol' the stepping magnet '416 to'battery and ground. Magnet 416 energiz'es preparatory to adff'ancing'the brushes of :the control switchw-hen its `circuit is opened.: -editer thelast-impulse has been transmitted, relay 400'fremains energized fora period of-V time suticient to permit the release of the slow relay 405.' Relay- 405iopensfthe circuit of stepping magnet 416,/which inA turn deenergi'fies and' advances the brushes 411", 5412", 413',

414 and 415 to their second-position terininals.

The two movementstep by-step selective switch has thus been positioned in accord?L ance with the oiii'ce code to determine the operation `of: the district and oiice switches to route the call inthe properdirection. The calli'ngsubscriber continues to manipulate his vdial to transmit the digits correspondingto" the numerical designation of the wanted line.v In =a ten thousand line oiiice the subscribers line numbers consist ottour digits and!` consequently four numerical registers 540, 545, 550 and 555' .are provided to take a'record of these: numbers. lVheny the dialk lO-lf'is oper-ated to transmit ther first digit Otfthewanted'num'- ber. relay '400lbecomes deenergized and com# pletes a circuit from ground through Vits" armature and backv lcontact, right-hand armature and front eontactof relay 404, winding olf relay 405, brush 412,1terminal 418, con-` ductor 429,"wi1idiiig-of stepping magnetf54l to batte-ry andiground.i Magnet-541 ener- A circuitiis alsolclosetltort ie en thfel endi'ofthe first-'impulse advances the brushesA 542, 548, etc'. to .the iirst position terminals.;` In `a similar manner, for each succeeding impulse inthe series, the brushes ofl register 540 are advanced `step-by-step until a -position corresponding to the first digitris reached.` Relay 405 completes the circuit above traced for the stepping mag net 416, and at the end of the series this relay releasesl toi-permit tl'iewdeener-gization ofsaidfmagnet; 'Ili'e'brushe's 411, 412, 413,` etci, of the"controlf switch are advanced to their fthi'rdposition terminals.

'Ilhefirsti deenergization otrelay 400y in response tovt-he` transmission of the Asecond series of `impulses of the '-zwantedline number causes a circuit 1to be1closed `from ground througlrth'e armature andfront contact of relay 404, winding of relay 405, brush 412, terminal 419, conductor 430, Swinding. of steppingmagnet 546 of V'the next register', tof' batter 1 and ground. The register 545 iszthereupon moved forward step-by-step in response tothe second serieslof impulses. Relay 405'closes thelabove traced circuitfor thestepp'ing magnet 416, and at the end of the' series opens this circuit to permit the control switch to advance tothe fourth position.

In `a Vsimi-larimanner the next and the last series otimpulsesare directed to the stepping magnets 5512and 556 of the registers 550-and 555 respectively, and these registers talreup their corresponding positions. Following the transmission' ot the last series 01"- impulsesv thel controly switch is advanced to'V its. sixth position.

Thelcircuits of this systemnare arranged to start the-district and ofiice selections immediately following the setting of the translator switch, or,-in other words, as soon as the record of the called otlice has been received. Y lVhileithe district and oltic'e switches are be'ing-'positioned the subscriber may continue the dialingoperation to register the` number of theycalled line.

Immediately afterv the` translator switch hasbeen positioned, theI control switch is moved-toitssecond position' terminals as explained. v Acircuit isthen completed from grounded battery through the winding ot relay 407, terminal 435, brush 414`to ground( Relayl .407 becomes energized and locks up in thercir'cuit@ extending through i its'- left'- hand.v armatureV and ifro'nt contact to ground by way` of` a `contact loii"s'e^qiieiice switch`v spring 499.` Relay407 completes circuits at itsl right-hand armatures for simultaneously ,recording on theregister relays of Fig. 5 vthe registration which controls the selec vtion of a brush 'set/at the districtselector.

Itrmight'be'well to observe at this point that relays 601, 602, 603, and 604 are used to Vset-iup a registration lin accordancelwith which 4classsequence--Switcli 410 -4will 'be' Cil Cal

positioned. As previously explained the setting of sequence switch 410 will control the routing of the call. Relays 613, 614, 615, 616, 617 and 618 are used to control brush select-ion both at the district switch and at the oiiice switch. Relays 606, 607, 608, 609, 610, and 611 are used to control group selection both at the district switch and at the office switch.

The class controlling relays 601, etc., and the district brush control rela-ys 613, etc., are positioned simultaneously under the control of impulser 623 in accordance with the position assumed by the translator brush set. The class sequence switch then hunts a position determined by which one of the class control register relays has been actuated. The sender sequence switch is then advanced and district brush selection takes place under cont-rol of the counting relays in accordance with which one of the chain of relays 613, etc. has been actuated. After brush selection at the district switch the sender sequence switch is advanced and allows the district brush controlling relays to be released. The district group controlling relays 606, etc., are then brought under the control of the impulser 623 and a registration accomplished to control the selection of a desired group in the district. After the district switch has completed group selection the district group controlling relays are released and relays 613, etc., are again brought under the control of the impulser to control brush selection at the oiiice switch. The completion of brush selection at the oHice brings about the release of relays 613, etc., and causes relays 606 etc., .to be associated with the impulser to cause a registration in accordance with which oice group selection may be accomplished.

Returning now to the detailed description of operation, the energization of relay 407 completes a circuit from grounded battery, winding of relay 621, Fig. 5, right-hand armature and back contact of relay 600, conductor 624, contacts of sequence switch spring 498, outer right-hand armature and front` contact of relay 407, conductor 625, translator brush 511 and its associated contact, brush 626, a conducting portion of the constantly rotating drum of the impluser and thence to ground as soon as the impluser brush 626 is brought into an engagement with the conducting portion accessible to it. It should be observed at this time that the impulser 623 comprises a constantly rotating drum driven by any suitable source of power and comprising a number of conducting and insulating segments served by a plurality of brushes. In order to more clearly show the relation between the various segments on the drum it has been developed into a plane surface. As shown in the drawing, conducting portions of the drum are indicated in black.

Relay 621 is energized in the above traced circuit and prepares, by way of its armatures, circuits for relays 601, 602, 603 and 604. Of these relays only relay 603 will be energized due to the fact that while brush 626 is in engagement with a conducting segment, brush 627 is the only other brush to engage a conducting segment. The circuit of relay 603 extends from grounded battery, left-hand winding of relay 603, conductor 628, armature 629 and its front contact, conductor 630, brush 627 and the conducting segment engaged by it, to ground. Relay 603 is energized in this circuit and completes a lockingcircuit -for itself from grounded battery, right-hand winding of relay 603, right-hand armature and front contact of relay 603, winding of relay 600, conductor 631, outer right-hand armature` and back contact of relay 471 to ground. Relay 600 is energized in this circuit and completes a circuit from grounded battery, power magnet of class sequence switch 410 (Fig. 4) lower right-hand Contact of sequence switch spring 408, inner right-hand armature and back contact of relay 471, conductor 632, left-hand armature and front contact of relay 600 to ground. Class sequence switch 410 is put into motion and continues in motion until relay 471 is energized. The control of the energizing circuit of relay 471 is successively shifted to the various class control relays by way of the contacts of sequence springs 472 and 473. When sequence switch 410 reaches position 7% a circuit is completed from grounded battery, winding of relay 471, lower righthand contact of sequence switch spring 47 2, upper right-hand contact of sequence switch contact 473, conductor 633, left-hand armature and front contact of relay 603 to ground. Relay 471 is energized in this circuit and locks up through its left-hand arma-- ture and front contact to ground by way of the contact of sequence switch spring 497. The energization of relay 471 opens at its inner right-hand armature the drivingV circuit of sequence switch 410 and causes the sequence switch to come to rest in position 8, which it will be assumed is the position in which a full mechanical call is to be set up. The energization of relay L171 also opens at its outer right-hand armature the locking circuit for relays 603 and 600 and these relays deenergize. It should be observed that when relay 600 was energized the circuit for relay 621 was opened and this relay deenergized. This however, is without effect since relay 603 remains locked up as previously described.

As soon after the energization of relay 407, as brush 634 engages a conducting segmentof the impulse drum, a circuit is comllt) fao

pletedv from ground,.brush 634 and its associated segment, conductor 635', inner righthand armature and Jfront contact of relay 407, lower contact of sender sequencespring 496, conductor 495, right-hand armature` and'back `contact of relay 612, winding ot'- rclay 619 to grounded-battery; Relay' 619 ,is energizedA and; prepares through its armatures circuits for relays 613 to 618 inclusive. Duringthe time that brush63`4 is engaging a conducting segment of the drum, brush (SSGis the only other brush to be engaging; a conducting segment. theonly relay to be energized at this-time. The lcircuit ot" relay G13 extends from gromided battery, lett-hand winding of relay 618, armaturev Gfrand its front con tact, brush 636 and the associatedV conducting segment of they impulse drum to ground. Relay 613 is'energized in this circuit and completes a locking circuit yfor itself from grounded battery, right-hand winding of relay 613, right-hand armature and front contact ofrelay 613, winding. of relay (512, conductor G38, upper contact-of sequence switch spring 494 to ground.- The energizationof relay 612 opens at its righthand aramature the circuit of relay 619V and At its lett-hand this lrelay deenergizes. v armature relay 612 completesy a circuit :trom grounded battery, power magnet of sender sequence switch 440, lower Contact of sequence -switch spring 439,-conductor 493, left-hand armature and frontcontact of relay 612 to ground, for moving this sequence switch out ot position 1 and into `position 2.

iis soon as sequence switch 440 reaches position 2 a circuit is completedt from groi-inded-` battery, left-hand winding of line relay 2121 (Fig. 2), upper rigl1t'liand and lower left-hand contacts of sequence switch spring 251, right-hand armature. and frontrontactof relay 207, brush 242 and its associated terminal, contactv oi' sequence switch spring 447, contact` ot sequence switch spring 442, winding of steppingfrclay 445, armature and back contact of relay 466 and the contact ot sequence switch spring 444 to ground. Relay 212 is energized in this ciri cuit and locks up through its left-hand armature and front contact to the above traced circuit by way ofthe left-hand contacts of sequence switch 251,. The energization ot relay 212 also completes av circuit trom grounded battery, powermagnet 'of sequence switch 210, upper lett-hand Contact ot sequence switch spring 215, right-hand R'elay 613' is therefore,

hand armature and front contact of relay 212, lower contact otseqzuence switch spring 213 to ground. The energization ofy magnet 224 causes the brush shaft 248'to be moved upwardin a brush selecting movement.

It should be observed that stepping relay 445Y was energized in series with the line relay 212.' The energization of relay 44:1 completes a circuit from ground, armature and conta-t of relay 445, upper contactotl sequence switch spring 464, conductor 465,v lefthand armature and front contactot' relay 613, conductor 639, (Fig. 5 and in Fig;` 4' that part ot conductor 639 connected to the vcontact of relay 492) left-hand armature and"backcontact ot relay 492, the winding oic the No. 0 counting relay, and contactr ot' sequence switch spring 491 to grounded battery. The No. O countingrelay is energized in this-circuit. As the brush shaft 248 *ap-- preaches the first brush tripping position coinmutator brush 228 engages a conducting portionotl commutator 230 and completes a holding circuit for relay 212 extending from grounded battery, winding of relay 212, up-` per left-hand contact of sequence switch spring 251, upper right-hand contact of sequence switch spring 220, a conducting, por tion ofA cominutator 230, commutator brush 228, and the Contact of sequence switch spring'223 to ground. Stepping relay 445 .is deenergized in this circuit and allows the No. 0 counting'relay andy relay 466 to be energized in the well known manner. The energization of theO relay completes a -circuit from grounded battery, power magnet` of sequence switch 440, upper le'lthand contact of sequence switch spring 459, left-hand armature andfront contact of the No. 0"'counting relay to ground, for moving this sequenie switch out of position 2 and into posit-ion 3. The energization of relay 466 opened the lower branch of the holding circuit of relay 212 and when a moment later commutator brush 228 engages an ins sul-ating segment ot coininut-ator 230, relay 212 is deenergized, opening at its right-hand armature the circuit ot up-drive magnet 224 and bringingthe brush shaftto rest in a position wherein the iirst set ot brushes may be tripped. The deenergization of relay 212 alsov completes a circuit from grounded battery, power magnet of sequence switch 210, upper right-hand Contact of, sequence switch spring 2115, right-hand armature and back contact of relay 212, `and the lower contact ot sequence switch spring 213 to ground, for movingthis sequence switch out ot position 4 and intovposition 5.

Referring now to the sender circuits it should be noted that when sender sequenre switch 440 left position 2 the locking circuit tor the counting relays is opened at sequence switch springs 490Y and 491 andy these-relays arel deenergizeda At the' 'saine time the locltingY circuit of relay 613 and relay 612 is opened at sequence switch spring 494, and these relays deenergize.

Vith the sequence switch 440 in position 3 circuits are completed for setting the group controlling register relays of Fig.5,as soon as brush 640 engages a conducting segment of the impulser drum. 'Vhen this occurs a circuit is completed from grounded battery, winding of relay 620, right-hand armature and back contact of relay 605, conductor 641, upper contact of sequence switch spring' 489, conductor 642, translator brush 513 and its associated contact, brush 640 and a conducting segment of the impulser to ground. Relay 620 is energized in this circuit and prepares circuits for relays 606 to 611 inclusive. Since brush 643 is the only other brush which engages a conducting segment of the impulse drum while brush 640 is effective, only relay 609v can be energized. The circuit of relay 609 extends from grounded battery, left-hand winding of relay 609, armature 644, and the front contact of relay 620 associated with it, brush 643 and its associated conducting segment to ground. Relay 609 is energized in this circuit and locks up through its right-hand winding and right-hand armature and front contact through the winding of relay 605, conductor 645, to ground, at the lower contact. of sequence switch spring 494. Relay605 is energized in this circuit and at its righthand armature opens the circuit of relay 620, which thereupon releases. Relay 605 at its left-hand armature completes a circuit from ground to conductor 488, upper righthand contact of sequence switch spring 439, winding of the power magnet of sequence switch 440 to grounded battery. Sequence switch 440 is caused to move out of position 3 and into position 4 upon the completion of this circuit.

lVith sequence switch 440 in position 4 and the district sequence switch in position 5 the fundamental circuit is again completed as above traced to control group selection at the district switch. This circuit corresponds to the one hereinbefore traced with the exception that the contacts of sequence switches 210 and 440 are closed in different positions. Relay 212 upon energizing in the fundamental circuit closes a circuit for driving switch 210 out of position 5 and into position 6. This circuit leads from battery through the winding of the magnet 210, left-hand contact of sequence switch spring 215, front contact and right-hand armature of relay 212, and the lower contact of sequence switch spring 213 to ground. Relay 212 remains energized in position 6 of sequence switch 210, in a locking circuit extending from grounded battery through its left-hand winding and contact, and left-hand armature, and the upper left-hand contact of sequence switch spring 251 to ground over the funda-mental circuit as described. Relay 212 again closes the circuit for the up-drive magnet 224 over the right-hand contact of sequence switch spring 218. Brush shaft 248 is advanced and brushes 233, 234, and 235 are tripped into engagement with the terminals of the bank due to the fact that trip magnet 225 was energized in positions 5 to 6 of sequence switch 210 by way of a circuit extending from grounded battery, winding of magnet 225, contact of sequence switch spring 221 to ground.

The stepping relay 445, which again energized in the fundamental circuit completes a circuit from ground through its armature and contact, lower Contact of sequence switch spring 464, conductor 487, left-hand armature and front contact of relay 609, conductor 646, (Figs. 5 and 4), armature and back contact of the No. 3 counting relay, and the winding of the No. 3 counting relay to grounded battery by way of sequence switch spring 491. rl`he No. 3 counting relay becomes energized and completes a series holding circuit for itself and the No. 3 counting relay. As the brush shaft 248 approaches the first group of terminals, commutator brush 227 engages the first conducting` segment of commutator 231 and a circuit is closed from battery through the left-hand winding and contact and lefthand armature of relay 212, upper left-hand and lower right-hand contacts of sequence switch spring 251, conducting segment of commutator 231, brush 227, contact of sequence switch spring 223 to ground. Relay 212 remains energized and the stepping relay is shunted down. Relay 445 deenergizes and permits the energization of the No. 3 counting relay in series with the lTo. 3 counting relay. As soon as commutator brush 227 engages an insulating segment of commutator 231, stepping relay 445 is again energized and causes the energization of the No. 2 counting relay` The counting relays are successively operated, until the No. 0 and No. 0 counting relays are energized, and the fundamental circuit is opened. The No. 0 counting relay closes a circuit including a contact of sequence switch spring 439l for advancing the sender sequence switch out of position 4 and into position 5. As sequence switch 440 leaves position 4 the contacts of sequence switch springs 490 and 491 are opened. and the counting' relays are all restored. In position 5 of sequence switch 440 the holding circuit of' relays 609 and 605 is opened at the lower contact of sequence switch spring 494 and these relays are released.

As soon, following the opening of the fundamental circuit at tie armature and Contact of relay 466, as brush 227 encounters antinsulating segment of the 'commutator 231, relay 212 hecones deenergized and operi's'the circuit of tl'ieup'drive power magnet 224. Relay 212'also closes a circuit from ybattery through the winding ot sequence" switch magnet`210, right-hand con.- tact ot' sequence switch' springI 215, hack contact'aiid right-hand armature of relay 212, lower contact of sequence switch spring 213 toground. Sequence switch 210 thereby advances 'from position 6 into position 7. With the district. sequence switch 210 in position 7,l a circuit is immediately closed from grounded battery through the. right- Contact of'sequence switch sprinr 21et, upp`er Contact lof sequentie switch vsp`1"r"ing208, contactl and? rigl'it-hanfcl arinatuievzot"relay 206 to ground;y Relay 212 becomes energized and completes a circuit from battery through the' winding of sequence `switch inagnet 210, le'iftliand Contact of sequence switch spring 21:5", 'front Contact and right-hand armature of relay`212,l upper Contact of sequenceswitch spring 213, right-hand armature andcontact of relay 205 to ground. y It will 'loeZ noted 'that relay was energized in position 2 or' sequence switch 210 inv a circuit iircluc'ling the upperri'ghtihand contact of sequence switch'spring'209. The sequence switch 21() advances out of position and into position 8; Relay 212 re-i mains :operated provided thev trunk yin the group upon the terminals of which the brushesvr 233, 234." and? 235 are standing is husy. In' this case the' test brush 235 is standing on a grounded test terminal andy the following locking circuit is closed for relay. 212: grounded battery, through the lett-hand winding and contact and lefthand'armature of relay 212, upper contacts ot'sequence switch spring 222, brush 235, and thence to the grounded test terminal ot the busy trunk. It will he notedthat the upper lett-hand contact 'oit sequence switch spring |222` does not/close 4until in position 'T1/g. This closure, however, takes place prior to the opening of the original energia ing circuit o l relay 212, as the lower left hand Contact of sequence switchk spring 214. opens when sequence switch 210 moves out oi position 71/12. Relay 212 remaining ener` gized, a circuit is completed for the updrive power magnet 224, from grounded battery through the winding oi'l said magnet, right hand contact of sequence switch spring 218, front contact and right-hand armature of relay 212, lower Contact of sequence switch spring 213 to ground. The brush shaft .2458 is driven upwardly and brushes 233A and 235 pass over the bank terminals to search for an idle trunk. filonV the first idle trunk is encountered,lno ground potential being found on the test terminal 238 thereof, relay 212 becomes ldeenergzed and votposition 3 and into posit ODS net vRelay 212 also closes a circuit as follows for driving sequence switch 210.out` y y 'non 10H: grounded battery, through the windingot Vthe magnet or' said `sequence switch, rightfhand contact of sequence switch spring 215, hack contact and rightehand armature of relay 212, lower Contact oil sequence switch spring 213 to ground. l, y y ,s itlr'sejuence switch 440 in position .o circuits vare completed for positioning thiehrush selection controlling relayswof Figure 5. As soon as yhrusl'i 6217 engagesa con ducting" segment of the `impulser drum, a circuit is" completed from groiui'ded battery, winding" of relay 619, right-hand varmature and baclzg'contactuof relay 612, conductor 495, upper right-hand'contact sequenceA switch spring 496, conductorlS, translator brush 5,1412 `and its associated terminz'i'l,im?`

)ulser brush 6417 and a conducting` segment of y a c z:

the impulser drinn to ground. y Relay 619y is energized 1n this circuit and prepares circuits' forkrelays 613 to (S13-inclusive. Sncethrush 6459 is the only other brush which engagesv a conducting segment` or' the ilrnpulser drum while brush 647 is e'ective, only relay 6,14 can bey energized. i The circuit of relay 6,14v extends: from ygroundedy battery, left-hand winding of relay 614", armature and frontI con't'ac't of relay 619,' brush 649 and its asso-f ciated conductingsegment to ground. Relay 614rlvlis energizedin this circuit andloclrs up thil'ougli its right-hand windin'gyand righthand armature and front contact through the' winding" of relayA 612, kconductor 638,

and the )upper right-hand Contact of se quencel` switch spring 4,94 to ground. Relay 612Mis` energized in this circuit. and at its right-hand armature vopens the circuit4 of relay 619, which thereupon releases.` Relay 612 at its left-hand armaturecompletes a circuit Vfrom ground to conductor 4193, lowerv left-hand Contact of sequence switch spring .hemmt 'of the updiiyg. power mag-j 439 and the ywinding ot' the power magnet of sequenceswiteh l1410 to grounded battery. Sequence switch MOis caused to moved out of .position 5 and into position 6 upon the completion of this circuit. r

lith sequence switch 140 in position 6 and the district sequence switch in position 1()conditions have been established for controlling the setting of the office selector switch shown in Figure 3. The funda` mental circuit is again established at this timey and extends from grounded battery through the right-hand winding of relay 300, lower left-hand contact of sequence switch spring `306, left-hand Contact of seqllnce. switch spring 305, conductor 239,

terminal 236, brush y233, right-hand contacts of sequenceswitch spring 2&6, conductor254,.righthand armature and front contact of relayf207, brush 24:2 and its associa-ted contact, contact of sequence switch spring 447, Contact of sequence switch spring 443, winding of stepping relay 445, armature and back contact of relay 466, contact of sequence switch springl 446, brush 243 and its associated contact, conductor 255, right-hand contacts ot sequence switch spring 247, brush 234, terminal 237, conductor 240, contact of sequence switch spring 304 to ground. Relay 300 becomes energized and closes a circuit from ground through its left-hand armature and front contact, lower left-hand contact of sequence switch spring 303, winding of sequence switch magnet 310 to battery and ground. Sequence switch 310 advances out of position 1 and into position 2. Relay 300 remains energized in a locking circuit from battery through its right-hand winding, its outer right-hand armature and front contact, lower right-hand Contact of sequence switch spring 306, left-hand contact orn sequence switch spring 305 and thence to ground as traced over the fundamental circuit. Relay 300 completes a circuit for the up-drive magnet 317 from groundedbat-V tery through the winding of said magnet, lower right-hand and upper left-hand contacts ot sequence switch spring 302, lefthand armature and front contact ot relay 300 to ground. The brush shaft 326 is thereby advanced under the control of magnet 317.

Stepping relay 445 is energized in the fundamental circuit, and completes a circuit rom ground through its armature and contact, upper contact of sequence switch spring 464, conductor 465, left-hand armature and front contact of relay 614, conductor 650, (Figs. 5 and 4) armature and back contact of the ilo. 1 counting relay, winding of the No. 1 counting rrelay to grounded battery, by way of the contact of sequence switch spring 491. The No. 1 counting relay is energized and prepares a locking circuit for itseltl and the No. 1 counting relay. Each time a conducting segment of the commutator 314 is encountered by cominutator brush 312, a circuit is completed trom grounded battery through the right hand winding of relay 300, its right-hand armatures and front contacts, right-hand contacts of sequence switch spring 306, conducting segment of commutator 314, brush 312 to ground. Relay 300 remains energized in this circuit and stepping relay 445 is shunted down. Consequently' the counting relays are successively energized and locked up in the well-known manner until finally the zero counting relays are operated. The fundamental circuit is then opened at the armature and contact of relay 466, and a circuit is completed from ground through the armature and contact of the No. 0 counting relay, the upper 1efthand Contact of sequence switch spring 439, through the winding of sequence switch magnet 440 to battery and ground. Sequence switch 440 is advanced out of position 6 and into position 7 whereupon the actuated counting relays are deenergized, and the holding circuit ot relays 612 and 614 is opened at the upper right-hand contact of sequence switch spring 494.

As soon after the opening of the fundamental circuit at the sender, as brush 312 engages an insulating segment on commutator 314, relay 300 releases its armatures and opens the circuit of the 11p-drive magnet 317. Relay 300 also completes a circuit from ground through its left-hand armature and back contact, lower right-hand contact ot' sequence switch spring 303, winding ot sequence switch magnet 310 to battery and ground, for moving this sequence switch out ot' position 2 and into position The brush tripping magnet 318 is now energized in a circuit closed over the lower Contact of sequence switch spring 309. Magnet 318 rotates the trip spindle in order to cause thesel'ected set ot' brushes to be trippedV on the neXt upward movement olt' the brush shaft.l

lVith sequence switch 440 in position 7, circuits are completed for positioning the group selection controlling relays ot' Fig. 5, as soon as brush 652 engages a conducting segment ot' the impulser drum. When this occurs a circuit is completed from grounded battery, winding of relay 620, right-hand armature and back contactot'- relay 605, conductor 641, vlower contact Vof sequence switch spring 489, conductor 651, translator brush 515 and its associated contact, brush 652 and the con-ducting segment of the impulser to ground. Relay 620 is energized in this circuit and prepares circuits for rclays 606 to 611 inclusive. Since impulser brushes 627 and o both engage conducting segments of the drum during the time that brush 652 is effective, relays 611 and 608 will be energized'. The circuit ot' relay 608 extends from grounded battery, lett-hand winding oi' relay 608, armature and :t'ront contact of relay 620, brush 627 and its associated conducting segment to ground. The circuit otl relay 611 extends trom grounded battery, lett-hand winding ot relay 611, armature and front contact ot relay 620, biush 653 and its associated conducting segment to ground. Relays 608 and 611 are energized in this circuit and lock up through their right-hand windings and right-hand front contacts and armatures to conductor 654 in parallel, and thence through the winding of relay 605, conductor 645, and the lower right-hand contact of sequence switch spring 494 to ground. Relay 605 is energized in this circuit and at its right-hand armature opens the circuit upper right-'handcontact of sequence'switch f 439, winding ot'yt-hey powerv inag-neto sen quence switch 440 fto. ground? switch-440 iscause-dto move out ot' position 7 and,I into 'position 8.

VVtlioiiice sequenceswitch 310 in position 3 and the sender sequence switch in position 8 the fundamental circuit is againv closed 4to, control the p group, selecting' movement of thedofiiceswitch. The Afundamental circuit may be traced over the path herein` before described.I Relay '300 becomes Ven'- ergized and closes a circuit from ground through its left-,handarmature and front contact, lower yleft-hand ,contact of .sequence switch fspringdOA,jwinding.- of the power magnet'oic sequence. switch 31,0 to grounded battery', for rmovingthis sequence switch out of position4 Sianjd'into position 4. In this position relaygQO remains energized kin a locking circuit from battery, through its rightha-nd windingA74 right-hand armatures andfront contacts, and thelower right-hand contact of sequence switch spring 30nd to` ground, as'ypreyiouslydescribed. Relay 300 prepares A the operating circuit of the updriye lmagnet` 317,l which includes the llower righthand andjnpper left-hand contacts of sequence switchspring 30,2. ,The brush "326 isV now driven yupwardly in agroup selecting movement.. n

Referring `#howto the sender it, should be noted that ythe lgenergization'oi relay 611 in the group.' controlling registering "relays causes the energizationgof translator relay 492; vT he circuit oi relay 492 extends from grounded batterythroughthe winding' of saidrclay andthence to ground at the leit-` hand armature and front ,contact of relay (311. 'When stepping relay ..445 is energized inthe fundamentalcircuit, a circuit is coinpletedfrolnground l*through thearmature l and contact of the stepping relay, lowercontact offsequence switch spring1464, conductor 487, lett-hand `armature front contact yof relayGOS, conductor, (Figs. 5 and 4) ysequence'V switch spring 306, conducting-segarmature and i back .contactI ot' No.L 2 countlng relay, windmg ofA ment of commutator 315," brush 311 to ground. down the stepping relay andfpermitsthe venergization oi'ffthe No; 2. counting relay.

As brush Ashaft 32.6' is advanced-the counting vrelays Vare successively energized due to the action of commutatorbrush 311 on commutator `315.A It'sho'uld benoted'that in theI present instance, with thev translation relay 492. energized, the Nos: Ol and.' O counting relays are Ynot energized after the No. 1 counting relay has been actuated. The energizationot the`..No. 1 counting The clo'sure'otl this circuit shunts.

stepping` relay 445 to conductor 639r and thence to the right-hand armature and front` Contact of Vrelay 492,v the righthand' armature and back contact of the No. 9 counting relay and the winding of the No. 9 counting relay. to ground. The successive actuation ot' the countingrelays con` tinues until the No.' 5 counting relay is energized. The next energization of steppingv relay445 extends ground by way of the rightfhand armature and. front contact of the No.5 relaythe left-hand armature and front 'contact of relay 492,jwinding-oiI counting relay No. O, andthe contact` rof sequence switch y spring A491 to Igrounded battery. `The No. 0 counting'frelayfis energized in this. circuit and upon the subsequentdcenergization of, stepping relay 445allows the \To.- O countingrelay and relay 466 in' parallel tlierewithto be energized. The energization oi` relayl 466 opens the lower branch of the fundamental circuit while the energizationof" the No.0 counting relay completes a circuit including fthe'contact of, sequence switch spring439 for driving sequence switch 440 'out of position.

Short-ly affter `the fundamental circuit is openedat the sender, commutator brush 311 engages an linsulating. segmentof thecom mutatorpl and relay l300 is deenergized. Relay 300 opens the circuit ofthe up-drive magnet 317- and brings the brush shaft with kthe selectedset.y of brushes/into operative relation with lthe eighth group of outgoing t-runl;s The deenergization of relay,l 300 also completes a circuitfrom grounded batf tery, winding. ofthe'power magnet sequence I switch 810, lower right-hand contact` of se- .quence' switch' spring 303,y left-hand arma-v closes a circuit `from Aground kthrough its left-hand armature and ftront contact, lower left-,hand contactjof .sequence switch spring* 303,` winding-ofthe power magnet otfsef..

Cil

quence switch 310 to battery and ground for advancing sequence swit-ch 310 out ot position 5 and into position 6. Relay 300 remains energized in this position, provided that the tirst trunk in the selected group upon the terminals of which the brushes 320, 321 and 322 are now standing is engaged. The holding` circuit for relay 300 extends from battery through the right-hand winding, right-hand armatures and t'ront contacts oi said relay, right-hand contacts or' sequence switch spring 308. test brush 322 to the grounded test terminal 325. Relay 300 by remaining energized in position oitl sequence switch 310, completes a circuit tor the up-drive magnet 317 by way of the lower right-hand and upper left-hand contacts ot' sequence switch spring 302. lVhen the first set of idle terminals is encountered the circuit through the righthand winding of relay 300 is opened, due to the iact that no ground potential is found on the terminal 325. Relay 300 is however` held energized a moment longer due to the existence ot' a circuit from grounded battery, lett-hand winding ot relay 300, upper lett-hand and lower right-hand contacts of sequence switch spring 301, a conducting segment of centering commutator 316, commutator brush 312 t-o ground. lVhen, a moment later, brush 312 engages an insulating segment ot' commutator 316, at which time the selected brush set will be accurately centered on the terminals of the selected trunk, this circuit is opened and relay 300 deenergizes, and opens the circuit of the up-drive magnet and brings the brush shaft to rest. The deenergization of relay 300 also completes the circuit from grounded battery, power magnet of sequence switch 310, lower right-hand contact of sequence switch spring 303. left-hand armature and back contact of relay 300 to ground for moving this sequence switch out of position 6 and into position 7.

In position 7 relay 300 is again energized by means ot a circuit extending from grounded battery, lett-hand winding oit relay 300, upper contacts of sequence switch spring 301 to ground. Relay 300 now closes a circuit through the lower lett-hand Contact of sequence switch spring 303 to advance sequence switch 310 out of position 7 and into position 8. Relay 300 remains energized in position 8 of sequence switch 310 by means of a circuit from grounded battery through the right-hand winding and right-hand armatures and Jfront contacts ot relay 300, the lower contacts of sequence switch spring 308, conductor 327, terminal 238` brush 235, right-hand contacts of sequence switch spring 222 to ground.

After the otiice selector has been positioned to select trunk 328, 329, the sender sequence switch 440 advances to the positions assigned for controlling succeeding switches or other mechanism in accordance with the numerical portion of the designation as is clearly explained in Patent No. 1,395,977. November 1, 1921, to F. A. Stearn and F. J. Scudder. It should be noted that the locking circuit of relays 608 and (311 and the holding circuit of relay 605 are opened at the lower right-hand contact or' sequence switch spring 494 as soon as sequence switch 440 leaves position 8. These relays there'liore deenergize. The register relays of Fig. are now in their normal condition.

lVhen the complete connection has been established the sender sequence switch 440 reaches some position such as 14 and a circuit is closed from ground through the contact 448, brush 244 and its associated contact, upper lett-hand contact of sequence switch spring 214, and the right-hand winding ot' relay 212 to grounded battery. Relay 212 is energized and completes a circuit from grounded battery, winding ot the power magnet of sequence switch 210, letthand contact of sequence switch spring 215, right-hand armature and front contact of relay 212, lower contact of sequence switch 213 to ground, for advancing this sequence switch 210 out of position 10 and into position 15. As the sequence switch 210 leaves position 11 the upper right-hand contact ot sequence switch 209 is opened and the circuit of relay 205 is interrupted. Relay 205 remains energized by means of a. substitute circuit closed from battery through its winding, contact and armature of relay 204, right-hand armature and front Contact ot relay 205 to ground. Relay 204, it will be noted, becomes energized in series with the calling subscribers line over a circuit closed by contacts 200 and 201 as the sequence switch 210 reaches position 10%. This circuit includes the battery and theI left-hand winding of repeating coil 202.

When the district sequence switch 210 leaves position 11 relay 207 is deenergized and removes the busy condition from the multiple terminals ot' other sender selector brushes to permit this sender to be taken for use in extending subsequent connections.

At the time the sender sequence switch 440 reaches position 14 a condition is created for causing the release of the translator switch and the numerical registers. To release the translator switch a` circuit is completed from grounded battery, through the windingl of release magnet 502, ott-normal contact 532 and the contact o't sequence switch spring 438 to ground. The contact 532 is closed as long as the brush shaft of the translator switch is away from its normal position. Relay 502 becomes energized and causes the release of the switch in the well-known manner. At the same time a cifcuitiscompleted for restoring the -pro- -gression switch to itsnormalposition. l '1This circuit may be traced trom batte-ry Athrough the Ywinding of the stepping 4magnet 416, armature and hack contact ot' said magnet, conductor 477, brush 411, which it 'willihe recalled, is linengagementwi-th itsfifthotfnormal contact, Vand-.thence to grosindwby way of sequenceswitch spring 438. wMargnet 416 interrupts ,its-own' circuit and advances the lbrushes of the control switchruntil j'they reach `their tenth position .terrn.inals,y at which time brush 411 open-s the steppingv oircuit of said magnet. In .position 10pt-,the control. switch a circuit isestahlishedfrom groundthro-ugh the brush 414,terminal 478, conductor 47 9, thence throug yh the brushes 542, 547, '552 and 557and. the respectiyejoifnorn'ial contacts.- engaged by them, .and :thenceI to the #back contacts and armatures and windings of'. the respective kstepping magnetsy 541,546, 551.7and 556 ofthe-various numerical kregisters to groundedV battery The numericalregisters arethereby Arestored totheir normal positions, whereupon a yeircuitis completed from `ground through the Vbrushes 558, 553,l 548 and` 543Yand their respective `normal contacts, .terminal.!,437, brush 415, back Contact and armatureand winding of stepping n1agnetv416 tobattery and. groun'd Magnet .416 causesxthecontrol switch r to .take one .step to restore such switchr to its .normal position.

When the controlfswitch. reaches its normal `position a. circuit isr closedv from grounded lbattery through thenwinding of ,the power magnetvof sequence switch l,440, lower deftehand contact iot `sequence :switch springfz480, lterminal-.481, zbrushe411and. the contacter' sequence... switch 438 to` ground. :Sequence switch 440 isfthereuzpon .advanced Ato v.its normal position.

fWhen the y.district ...sequence A switch V'210 leaves;- position y101/2yt-he circuit of .relay :400

is opened andfthisrelay deenergizes, causing in. turnvthe-deenerg1za.t1onauf. relay 40,4.

WVhenthereore, :sequence :switch 440 reaches position r1 a :circuit is-completed for-restoringr-:the` class :register .i sequence switch-'5.410. -tThis circuit.; extends from gmundedtattery,

windinfr of the: werfmaenetaots uence switch .410, upper irightfhandcontactf of seandf104,en ergized` -Belay 104.011 deenergizi ng completes y.a circuit. as follows for re- .,storingfthe .individual linesswitch to its normal position.; g Y=gjr nin led fbattery, .wind ing `and 1 armature land back contact vot' stepping magnetg;q1.05 lowermost armature .and back quence switchy spring :408, Contact of sequence switch y spring .5482; i terminal 1,481,

brush .f4-11, rightfhand `@armaturef, andn v@back contacts yoffrelayf404, and 4the right-,hand ar- Aterrswiteh ,ftofbei` advanced out; of. position 8 andinto position :1.

MvNith the district sequence-,switch 210 yin .ping inagnet "10,5 interrupts its own circuit andfrestores -the'fbrushes 106, 107, 108, 109, 1,i110.- =.and 111, ytoetheir normal positions, whereupon the brush@ ,107 disengagesseg- ,position f v15 and the :oce A sequence switch 810 in position k8p@nconvfnsatienallcircuit is established :through 1f.to-,f the tru-nk 32811329. :'Whennthei callingrsubscrber datcrli hangs-mp .his=..recei\rer the circuit of' .relay 204 vis openedv `.Relay-.204 inturncausesthe deenergizationl-.ofrelay .205.' 4Relay 205.completes the circuit .from-.ground through its right-hand'.normal contact, the. upper .contacts ofsequence switch 219, and the windjngzof the power magnet ot the sequence switch.210.to grounded.battery, to cause thisrsequence..switch to move from position 15into position 18.

I1i..position .18,a. circuit iscoinpleted troni grounded battery, winding 'of ,down-drive mag-net 226, `1*.igc-flift-liand contacts oiiseqnence switch. spr-ing 219, to ground at the hack ycontact ofnrelay `205.. When the .brush shaft v2.48 Areaches its normal .posit-ion a circuit is .completed from ygrounded battery, ,winding otthe power .magnet of sequence switch 21,0, contact of.sequence switch spring 217, normalecommutator .segment 229, commutator brush :228 to ground. at sequence switch spring'1223or ino-ving sequence switch 210 ,out of positionlS andunto position 1.

v. As sequence switch 210leaves position 16 the holdingcircuit of Irelay 300 is interr-uptedmt the right-hand contacts ot se- 2quence switch spring5222., Relay 800 re- .leases ,its larniatures and completes a lcircuit from grounded battery, winding 'of the power magnet ofsequence switclrlO, lower -right-hand Contact ot' .sequence switch -spring `303, left-hand armature and back contactof relay a300 Ito, ground` ytor `moving :this.sequence,switch outotfpo'si-tion 8 and .intopposition v18.

. VWhen therbrushsha-ft 326 reaches itsnorrnal position grounded battery, lwinding lof the power .magnet otsequence switch 310,.upper rright- Ahand-contact ot sequence switchspring 803,

Ia V,circuit is completed ,from

.nQUnal eommutator segment 813, commutator brush :312 to ground, tormoving this vseipience.-switchout of position 18 and into iposition 1.

,Atqftheitime ,relay 205 becomesdeenergized it opens at its left-hand ,armature the 'circuitswhichhas lbeen holding relays 206 contact Vof relay 104, right-hand armature and back Contactofrelay{103,zbrush 107,l oii- `herrn-a1,,seg'muent 112 to ground. lThestepment 112 and opens the operating circuit 'of the stepping magnet. 4All of the apparatus has now been restored to its normal condition and is ready for reuse.

From the foregoing description it is obvious that the groups ot `register relays shown in Fig. 5 are operated only during the period immediately preceding and during the duration of the selective operation which they are to control. It is further obvious that each group otl relays may be used repeatedly to control selective operations ot a plurality of switches. In the embodiment shown relays 613 to GIS control brush selection at the district and otiice sclector switches. Relays 606 to 611 inclusive control the group selecting operations at the various switches and relays G01 to 504; control the setting` ot the class register switch. It is further obvious that the impulse generating device 623 is preferably common to all the senders ofV an exchange since its brushes may be multipled to the various senders in desired combinations and no possible confusion can result.

The usual advantage ot the use of a common impulse generating device in connection with a translator switch is thus attained. This advantage lies mainly in the simplicity in which a change ot routing may be accomplished. Then the translator switch is employed in combination with an impulse generating' device it is only necessary to change the connections to the brushes of the impulse generating device, and the changes are immediately effective on all of the senders. An additional set of translator terminals has been shown to further illustrate the method ot' connecting to the impulser 623.

that is claimed is:

1. In a telephone exchange system, a plurality of automatic switches, a primary registering device, a plurality of secondary registering devices, means to position said primary registering device, means to position eachl of said secondary registering devices a plurality of times in accordance with a single setting` of said primary registering device, and means to operate said automatic switches under the control of said secondary registering devices.

2. In a telephone exchange system, a primary registering device, a secondary registering device, means to position said primary registering device, and means to operate said secondary registering device a plurality of times in accordance with a single setting of said primary registering device.

3. In a telephone exchange system, automatic switches, a primary registering device, an impulse generator, means to position said primary registering device, a secondary registering device, means to operate said secondary registering device a pluralwaere@ ity ot times under the control of said impulse generator in accordance with a single setting of said primary registering device, and means to operate said automatic switches under the control of said registeri'ng devices.

4C. In a telephone exchange System, a primary `registering device, a group of relays comprising a secondary registering device, means to position said primary registering device, and means to repeatedly operate said relays in variable combinations in accordance with a single setting ot said primary registering device.

5. In a telephone exchange system, automatic switches, a plurality of primary registering devices, a secondary registering device associated with each of said primary registering devices, an impulse generator common to said primary registering devices, means to position a desired one ot' said primary registering devices, means to repeatedly operate the associated secondary registering device under the control of said impulse generator in accordance with a single setting ot' said positioned primary registering device and means to operate said automatic switches under control ot said registering devices.

G. In a telephone exchange system, a primary registering device, a group of relays comprising a secondary registering device, an impulse generator, means to position said primary registering device, and means to repeatedly operate said relays in variable combinations under the control of said impulse generator in accordance with single setting of said primary registering device.

7. In a telephone exchange system, a plurality of primary registering devices, a group of relays comprising a secondary registering device associated with each of said primary registering devices, an impulse generator common to said primary registering devices, means to position a desired one of said primary registering devices, and means to repeatedly operate the associated relays in variable combinations under the control of said impulse generator in accordance with a single setting of said positioned primary registering device.

8. In a telephone exchange system, a plurality of automatic switches, a primary registering device, a plurality of secondary registering devices, means to position said primary registering device, an impulse generator, means to repeatedly position each ot said secondary registering devices under the control of said impulse generator in accordance with a single setting of said primary registering device, and means to operate said automatic switches under the control of said secondary registering devices.

9. In a telephone exchange system, a plurality of automatic switches, a plurality of lill primary registering devicesl, a 'plurality ot secondary registering devices associated with each of said primary registering devices, an impulse generator common to said primary registering devices, means to position a desired one of said )rimary registering devices, means to repeatedly position each of the secondary registering devices associated with said positioned primary registers under the control of said impulse generator in accordance with a single setting of said primary registering devices, and means to operate said automatic switches under the control of said secondary registering devices.

10. In a telephone exchange system, a plurality of automatic switches, a primary registering device, a plurality of groups of relays, each of said groups comprising a registering device, means to position said primary registering device, an impulse generator, means to repeatedly operate said groups of relays in variable combinations under the control of said impulse generator' in accordance with a single setting of said primary registering device, and means to operate said automatic switches under the ,control of said secondary registering devices.

l1. In a telephone exchange system, a plurality oit automatic switches, a primary registering device, a plurality of groups of relays, each of said groups comprising a secondary registering device, means to position said primary registering device, means to repeatedly operate each of said groups of relays in variable combinations in accordance with a single setting of said primary registering device, and means to operate said automatic switches under the control of said relays.

l2. In a telephone exchange system, a plurality of automatic switches, a registering device, means to position said registering device, meansV to operate one of said automatic switches in a selective movement in accordance with the set position of said registering device, means to release said registering device as soon as the selective movement controlled by it is completed, and means operative thereafter to reposition said registering device to control another of said automatic switches.

13.' In a telephone exchange system, calling and called subscribers lines, a plurality of automatic switches for interconnecting said lines, a primary registering device, means to position said primary registeringdevice under the control of a calling subscriber, a plurality of secondary registering devices, means to repeatedly position each of said secondary registering devices in accordance with a single setting of said primary registering device, and means to operate said automatic switches under the control of said secondary registering devices.

14. In a telephone exchange system, calling and called subscribers lines, a plurality of automatic switches for interconnecting said lines, a primary registering device, means to position said primary registering device in response to a plurality of series of impulses transmitted over a calling line, a plurality of secondary registering devices, means to repeatedly position each of said secondary registering devices in accordance with a single setting of said primary registering device, and means to operate said automatic switches under the control of said secondary registering device.

In witness whereof, I hereunto subscribe my name this 9th day of Ag'il, A. D. 1921.

WALTER ALBERT. 

